Locking device



Dec. 25, 1945. R. A. MARTIN ET AL LOCKING DEVICE Filed Oct. 14, '1944 FIG..2.

Patented Dec. 25, 1945 LOCKING DEVICE Roy Arthur Martin, Hornchurch, and Alan William Say, Upminster, England, assignors to The Plessey Company Limited, Ilford, Essex, England, a company of Great Britain Application October 14, 1944, Serial No. 558,774 In Great Britain December 11, 1943 2 Claims.

This invention relates to an improved locking device, and has for its object to provide a very simple means for locking one, two or more rotary members against rotation.

In the drawing:

Fig. 1 is a front view,

Fig. 2 is an underside view, and

Fig. 3 is a section on line AB of Fig. 1.

According to this invention, a spring clip which is anchored against rotary movement embraces a drum fixed to a rotary member, and means, such as movable members, operatively connected to said clip are moved simultaneously in opposite directions, such as for example, by cam.means, thereby expanding the spring clip and allowing the rotary member to revolve freely, and when actuated in the reverse directions lock said rotary member against rotation.

The spring clip is made of varying cross section so that its second moment of area at any point is proportional to the bending moment at that point in order that the bore of the clip shall remain truly circular when deflected and so gri the drum uniformly when in the locked position.

A drum l is fixed to each spindle 2, which in turn is embraced by a spring clip 3. A U-shaped extension 4 is formed mid-way in the outer periphery of each spring clip 3 for receiving a pin 5 fixed to a common bracket 6, whereby the spring clips 3 are anchored against rotation. The free ends or each spring clip 3 terminate into short legs I between which engage the means for expanding said spring clips 3 as hereinafter described.

Two parallel bars 8, one of which is slightly wider than its companion, have complementary slots 9 near the respective ends, and intermediate apertures Ill. The slots 9 each receive a guide bar H integral with the bracket 6 whereby the respective bars 8 are free to slide in either direction. The said intermediate apertures l6 are adapted to receive a double acting cam I2 fixed to a spindle mounted in the bracket 6 and actuated by a knob M on the end of said spindle I3 as shown in Fig. 2.

Along one edge of the bars 8 are pairs of cooperating lugs l5. Each pair of lugs l5 overlap each other and are interposed between the legs I, so that, as the bars 8 are moved in opposite directions, by rotation of the knob M, the cam [2 moves the bars 8 in opposite directions, when said lugs l5 engage with the respective legs 1 of each spring clip 3' thereby expanding them, when all three spindles are free to revolve. Reverse I3, which in turn is rotatably' movement of the knob l4 releases the tension of the spring clip 3 when the bars 8 are moved in opposite direction through the engagement of the legs 1 with lugs [5, when all three spindles are locked simultaneously. The amount of expansion of the spring clips 3 depend upon the size or shape of the cam l2.

Preferably, the edges of the intermediate apertures l0 are in constant contact with the cam l2 by means of a spring I6 anchored to the respective bars 8 through rectangular apertures [1 whereby the lugs l5 are moved out of contact with the legs of the spring clip 3 when in the locked position.

The normal position of the knob I4 is preferably such that all three spindles 2 are locked against rotation.

If desired means may be provided for indicating when the locking device is engaged or free.

An advantage of this arrangement is that any one or more of the spindles can be set to a particular angular position and then locked in this said position, by the operation of a single control and that the locking device can be accommodated in a very confined space, which is an advantage when applied to a radio set or the like.

We claim:

l. A locking device comprising a support, at least one rotary element carried by said support, a drum fixed to the rotary element, a spring clip of varying cross section terminating with legs at its free end, the main part of said spring clip embracing said rotary drum, parallel bars of unequal width provided with complementary lugs and intermediate apertures, the lugs being interposed between the legs of said clip, a rotary cam. mounted in the apertures in said parallel bars, a control means associated with said cam for moving the parallel bars in opposite directions whereby the lugs integral with the parallel bars expand said spring clip, and said cam when actuated in the reverse direction removes the lugs of said bars out of engagement with the legs of said clip, thereby permitting contact between the spring clip and the drum so as to lock said rotary element against rotation.

2. A locking device comprising a support, at least one rotary element carried by said support, a drum fixed to the rotary element, a spring clip of varying cross-section terminating with legs at its free end, the main part of said spring clip embracing said rotary drum, movable members provided with complementary lugs and two sets of intermediate apertures, the lugs being interposed between the legs of said clip, a spring means coupled to the respective movable members and housed in one set of apertures in the movable members, a rotary cam means operatively connected to said movable members mounted in the other set of apertures in the movable members, a control fixed to the cam means, said cam means actuating the movable members in opposite directions for expanding the spring clip and in the reverse direction for releasing said spring clip, said spring means adapted to separate said slidable members from the spring clip at the 0115 position and by maintaining contact between the movable members and the cam means to locate the said control in both the on and off position.

ROY ARTHUR MARTIN.

ALAN WILLIAM SAY. 

